1. Field of the Invention
This invention relates to atomizers and more particularly to ultrasonic liquid atomizers.
2. Prior Art
U.S. Pat. application Ser. No. 269,935 now U.S. Pat. No. 3,904,896 to Guntersdorfer, shows a piezoelectric vibrating system for atomizing liquids. In accordance with the teachings of that patent, and particularly in accordance with FIG. 2 thereof, the vibrations produced by a piezo-ceramic transducer are transmitted to a liquid atomizing atomizer plate by means of a conical transformer member, see also U.S. Pat. No. 3,738,574 to Guntersdorfer et. al.
This prior known type of piezo-ceramic electric vibrating system can be protected against moisture or other fluid damage which can occur when an atomizing conductive liquids by supporting the conical transformer in the neighborhood of a vibrational mode line through an attached mounting ring. The mounting ring can then constitute the end of a housing defining member which encloses the piezoelectric vibratory system. In this manner, a portion of the conical transformer will be positioned interior of the housing defining member. The housing defining member can also contain the electric excitation system for the transducer as well as the transducer.
It is also known from German laid open patent application P23 08 584, the teachings of which are herein incorporated by reference, that liquid can be supplied to the atomizer plate by means of a bore provided through the conical transformer along the axis of rotation which intersects with the another bore positioned at the level of the mounting ring and extending perpendicular to the axis of rotation of the conical transformer.
During continuous operation of such above described piezoelectric vibratory systems, liquid filaments or films can develop at the edge of the atomizer plate. When this occurs, it is possible per the underside of the atomizer plate to also become partially coated with liquid. During atomizing, droplets of such liquid from the underside of the atomizer can then be accelerated onto the conical transformer. This has the disadvantage in that such contact with the conical transformer can alter the residence frequency of the vibratory system in such a manner that performance of the atomizer may be reduced. It would therefore be an advance in the art to provide a piezoelectric vibratory system of the type above described in which means are provided to prevent the formation of liquid films at the edge of the atomizer plate and to prevent the formation of liquid accumulations on the undersurface of the atomizer plate.